1. Technical Field
The present invention relates to a fluid droplet ejection device capable of inspecting fluid ejection from a plurality of ejection nozzles, and to an ejection inspection method.
2. Related Art
Japanese Unexamined Patent Appl. Pub. JP-A-2008-195037 teaches a printing device that performs a fluid droplet ejection process to check if fluid droplets are ejected normally from the ejection nozzles before printing starts. During this ejection inspection the printer taught in JP-A-2008-195037 inspects ejection from each ejection nozzle in the nozzle surface of the printhead, and if an ejection problem is detected in some of the ejection nozzles, substitutes other ejection nozzles that are operating normally to eject the liquid that should be ejected from the ejection nozzles that are not operating normally. The printer then prints and performs a cleaning process after printing ends to suction ink from the ejection nozzles or wipe the nozzle surface, for example. As a result, the end of printing is not delayed even if an ejection problem is detected before printing starts because printing can proceed with good results even without first performing a time-consuming cleaning process.
A problem with this printer, however, is that the ejection inspection process takes a long time because fluid ejection is inspected for every nozzle of the printhead. The inspection time could conceivably be shortened by only inspecting a subset of the ejection nozzles in any one inspection operation. However, if there is an ejection problem in any of the nozzles that are not in the group of inspected nozzles, printing will proceed with some nozzles not ejecting properly, resulting in print defects.